William Longespee is best known for his rather regrettable alliance with King John (which he later broke off), but before then he had served his other half-brother, Richard the Lionheart.
In fact, according to my research, Longespee went on a number of campaigns with Richard. He accompanied him on the Third Crusade and was at the capture of Acre.
While information is sketchy and cluttered by innuendo, pride, and differences in scholarship, it is widely accepted among historians that Richard was either gay or bi.
Here’s where it gets interesting: William married Countess Ela, which was arranged by Richard. Ela was at the time quite young (about nine years old). However, no one can accuse Longespee of being a dirty old man; judging by the records of Longespee’s family, there is no evidence he consummated their marriage before Ela was 22 years old. Clearly he was in no hurry and perhaps he was heartbroken by Richard’s death shortly after arranging the marriage for them.
While I cannot find specific sources, I have seen numerous references to Richard having taken “several of his knights” as lovers.
There is also the memory I’ve had of having been bisexual as William. That I cannot confirm, but it fits the known facts fairly well.
I also wrote a book some time ago that turned out to have several parallels with Longespee’s life, and one of them happens to involve a bisexual love triangle between a noble and one of his vassals; at the time I made the decision to do that, I thought I was really stretching history and I didn’t know about Richard.
It’s all vague and circumstantial and I can’t prove a thing, but I have a strong inkling that I was bisexual in my life as the Earl of Salisbury and that my earliest encounters may have been with my half-brother. It is stranger still to think that such a story is actually plausible.